1. Field of the Invention
This invention relates to detection of coil failure in an actuating solenoid of an electric power switch, and particularly to loss of electrical continuity through the coil due to a break in the coil winding.
2. Background Information
Electric power switches having an electronic control circuit typically have an actuating solenoid that is energized to actuate the switch when the electronic circuit detects a fault condition. For instance, when the electronic trip circuit of an arc fault circuit breaker detects arcing in the protected circuit, a trip signal energizes the actuating solenoid to interrupt power flow in the protected circuit. Unfortunately, the coil of the actuating solenoid may be damaged as a result of overheating or mechanical impact. Such damage may include a break in the coil winding, thereby rendering the solenoid nonfunctional. A failure of this type compromises the ability of the electric power switch such as the arc fault interrupter to perform its primary function.
There is a need, therefore, for apparatus which can provide an indication of failure of an actuating solenoid so that corrective action can be taken.